Door latch



G. A. SCOTT ETAL July 30, 1963 DOOR LATCH 2 Sheets-Sheet 1 i Filed Jan. 9, 1961 FIG.\

INVENTORS GEORGE A. scoTT 8MILTON s. w\|.\ \AMs IR.

July 30, 1963 G. A. scoTT ETAL DOOR LATCH 2 Sheets-Sheet 2 Filed Jan. 9, 1961 IN VEN TORS R I TS Y m dfn. A w m E5 m E OT. H E n.. GM T o@ Y B y.wherever it fis yfound advantageous.

United States Patent() v3,099,471 DOOR LATCH AGeorge A. Scott, Jeiersontown, `and Milton S. Williams, Jr., yMiddletown, Ky., assignors to General Electric Company, a .corporation of New York Filed Jan. '9, 1961,.Ser. No.81,371 10 Claims. l:(Cl. 292-7) The present invention relates to a latch mechanism tor holdinga pivoted .door in a closed position.

This invention was .iirst conceived during fthe .develop- `ment of a new concept in baking ovens Afor domestic use wherein the interior oven' walls .may be :cleaned automatically by a high temperature cleaning cycle. Such ia .high temperature oven is .described .in an earlier Acopending application of .Bohdan Hur-ko, Serial No. 27,926 ii-led May 9, .1960, which application is assigned Vto Ythe General Electric Company, lthe assignee of the .present invention. The :food soil grease .spatter that accumulates -on'fthe oven wall-s may .be completely removed automatically shy :raising .the ytemperature of the =oven to a -heat cleaning =temperature within the rangeof about 750' F. to :95 0 F. yso .as `-to burn off .all foreign `matter lfrom the loven walls. .ln such a high temperature .oven it is of primary impror- `tance to 4latch the door lbefore :the cleaning cycle lis ."set .motion .and the oven temperature is raised .above fthe .normal cooking Jtemperature of .about 550 This insures that the 4oven door may not be -opened before the --completion of the heat cleaning cycle, otherwise :a .Hash iire `or small explosion might occur. .Up until now iit has -never been necessary to latch an .oven .door in the closedposition as 'with someother'major appliancessuch .as .automatic dishwashers, refrigerators, and v.clothes dryers.

The primary object of the present .invention is l:to provide .a latch mechanism that .is easy to `operate vand of compact ysize for mounting either -in a door -or the fdoor frame, where the -latching means has a swinging motion which will pull the door closed tightly.

A further object of the present linvention vis to provide .a novel door latch where the latch means is :retractable out of sight when in the Iunlatched position.

A -further .object of the present inventionLis to provide a .door latch that may be mounted within .an oven 'door =and Where the operating .handle of .the :latch is capable .of linear motion ,and serves in .the :place of the rstand'ard fhandle for opening and closing the door `during the normal fuse of the oven.

.A still further object ofthe present invention .isto .provide a novel .door latch for use :.in a high temperature `oven -where the movement .of the ropera-ting handle .of =the latch lserves yto uncover the operating :instructions ,which vare -opening drop-door of an oven, it will .readily besapparent to those skilled in this art that such a smechanism :has general utility in the latch .art and it may f'be so :used

The latch fmecha- .-n'isrn includes ,an .operating .handle that is capable of linear motion and a pivoted latch means connected to :the operating handle by linkage means Vso that movement Iof `the handle will eiect a comparable movement `of ithe .latch means. .It -is important that .the .latch `means pull Patented .July 30 1963 v"ice 2 door opening. This action yis provided by an eccentric crank .means which serves as a shifting ipivotal raxis for .the .latch means.

Other improvements .are to provide a fixed stop tocooperate with the latch means so .ras to retract the latch ,means out .of sight 'when the .door is funlatched. .-A-lso a .return spring means may =be provided to lhold the operat- .ing handle .in .the latched position as well .as to .counterbalance .the .handle :and return .the handle fto the funlatched y.position once it is shifted slightly-y from the latched position. One of .the vmany advantages ot ythis 'type ,of -door lat-chis :that the operating handle 'has the appearance of a fstandardovendooiy.handle andit -functions as such .during normal .cooking oper-ations. Moreover operating instructions for the oven cleaning .cycle maybe positioned vbe- .hin-d y.the .operating handle out of sight during .normal .cooking and plainly in View -on'ce the .latch operating handle is .moved .to the Ilatched position.

Our .invention will be better understood from `.the 'following description -taken in vconnection with the accompanyingfdnawings and itsscope will .be tpointedout :in the vappended claims.

.FIGURE ..1 ris .a left side velevational view of a freestanding vrange .having an oven .fdoor'embodying the ila-tch .mechansim of .the present invention.

FIGURE 2 is la fragmentary vcross-sectional side eleva- :tional view taken' near the topi of Vthe yoven .door adjacent :the ydoor .handle and showing the latch .mechanism of .this invention -located within ythe door with :the operating handle moved downward .in la partially latched position.

FIGURE 3 :is a fragmentary is'ometrical crossfsectional `view taken-.on .the same plane vas FIGURE'2, but showthe door closed :tightlyso .that the door Vactually seals the d ing the operating handle in its lowermost -fully latched position. l

FIGURE 4 .is .an :isometric -View of the subassembly :of .the latch mechanism of the .present invention removed 'trom ...the .oven door and showing the :operating :handle -in the .unlatche'd position.

.FIGURE 5 -is :a diagrammatic showing of the return lspring that cooperates -w-ith the .rock shaft -of the latch mechanism illustrating,r the position 4of ,the spring when the -r'latch vmechanism is yin `its unlatched position of SFIG- FIGURE 6 is a. diagrammatic showing similar to that yof .FIGURE 5 showing the return spring in its overcenter position to constitute .a spring ybiasing force holdingthe operating lhandle :in its latched position.

Turning now to .a consideration of the -drawings and in particular "to AFIGURE l, there is shown for illustrative purposes only a free-standing electric range 10 having. a topcooking surface 11 .with aplurality of surface heating elements 12, an oven cavity '13, a'front-opening drop-.door 14, and a backsplasher 1'5 arranged `along the 'back edge of the cooking surface 11 and in which are llocated `the -various :manual controls ffor vgoverning the .energization fof fthe heating :elements ofthe range. 'Ilhis invention 'is :concerned 'with .a latch mechanism 'for locking .the oven :door'14 in the closed :position although -itsuse .is notrestricted to an .oven door. However, to give ya speciiic example of the utility of this latch mechanisml it lwillbe ifdescribed ,cooperation withantoven and thedoor ofithe oven. Accordingly, no further mention will be .made of lthe details of :construction -of .the .range T10. :since .they form .no ,part of :the .present invention.

.As `shown in FIGURE .l `the .oven door 14 is .hinged :along its bottom edge :about the .pivotal axis 16f.o`f .the :hinge :brackets `17 .that'are .in turn fastened .integrally to the body of lthe range 10. The :upper portion .of I.the rvdoor 14 is provided .on itsftront :face lwith :adoor thandle 18 havng the outward appearance of :a standard .oven door `handle that `is in use today. -I-Iowever, this door handle 18 :is :the toperating. handle :ofithe latchz mechanism of the present invention Ithat is positioned within the door as is best shown in FIGURES 2, 3, `and 4 of the drawings. FIGURES 2 and 3 show the latch in the partially latched position and the fully latched position respectively while FIGURE 4 is anisometric showing of the latch mechanism completely .removed from the door. Accordingly, the best understanding of this invention can be gained by referring to FIGURE 4 for a detailed explanation of its principle of operation.

The :two main elements of the latch mechanism are the operating handle 18 and the latch base 20. The l-atch base 20 is a sheet metal member of elongated shape that is welded or otherwise fixedly held within the oven door. The latch base 20 has a vertical back wall 21, a narrow top ange 2.2, and parallel side walls 23 which extend perpendicularly to .the back wall 21. As seen in FIGURE 3, the vertical free edges of the two side walls 23 are folded outwardly as at 24 to form side bearing rails that lie in a common plane parallel to the back wall 21. A hard surfaced sleeve 25 of low ftictional resistance such as glass filled Teon or an equivalent high temperature bearing material is formed over the rails 24 to serve 'as smooth rails on which the operating handle 18 is supported and guided for linear motion between the unlatched position of FIGURE 4 to the latched position of FIGURE 3.

The operating handle 18 is likewise an elongated member of .thin metal vstock having a decorative, outwardly projecting, hand-engaging portion 27, a deep recessed channel 28 behind the hand-engaging portion 27, and a vertical back surface 29 whose side edges are doubled back on themselves `as at 30 for nearly the entire height of the back plate 29 for encompassing the sleeves 25 of the side bearing rails 24 of the latch base 20. Accordingly, it should be understood that the operating handle 1-8 is capable of vertical reciprocating motion from a topmost or unlatched position to a lowermost or l-atched position.

One application of the novel latch mechanism of this invention is with the high-temperature oven having an automatic oven cleaning cycle. Since this design of oven is completely new to housewives and there are several operating steps which must be taken in sequence in order to initiate the cycle and retain absolute safety in the kitchen, it has been considered necessary to provide use and care instructions which are readily available when needed and are not seen during the normal use of the oven for cooking. 'Ihe purpose of the deep recessed channel 28 of the operating handle 18 is to `afford room for the incorporation of .an instruction panel 31 which is staked or otherwise fastened to an edge of an opening in the front panel of the oven door 14 Ito extend down into the recessed channel 28 as is best 'seen in FIGURES Z and 3. A typical set of instructions would be las follows:

(1) Set oven knob to clean.

(2) Turn oven temperature knob past clean and release when indicator light goes on.

(3) Open oven door only after light is out.

It is made clear by studying both FIGURES 2 and 3 that the operating instructions are hidden when the operating handle 18 is at its uppermost unlatched position shown in dotted lines in FIGURE 2, and is clearly visible when the handle 1-8 is in its lowerrnost latched position of FIG- URE 3.

'In addition to the operating handle 18 and the latch base 20, the latch mechanism includes a parallel pair of vertically swingable latch members 33, there being a latch member at each side edge of the back plate 21 of the latch base 20. These latch members 33 are each freely supported on a crank arm 34 of a rock shaft 35. 'I'he rock shaft is pivotally supported adjacent its opposite ends on parallel tabs 36 which project outwardly from the back plate 21 toward the operating handle 18. As best seen at the right side of FIGURE 4, the crank arm 34 is of generally L-shape having one portion extending vertically perpendicular to the pivotal axis vof the rock Shaft 35 and then a second portion extending at `a right angle t0 lie in a parallel relation to the pivotal axis of rock shaft 35. The latch member 33v is of folded U-shape crosssection throughout its length, as best seen 'at the left side of FIGURE 4, to give it the necessary -amount of strength and rigidity. It also has a hook formed on its free end 37 which is adapted to engage in a slotted opening or keeper portion 38 of the front wall of the door frame or oven body. The rock shaft 35 has another crank arm 39 located between the shaft supporting tabs 36 and disposed in a plane at slightly less than a right angle to the -plane of the L-shaped crank arm 34 zas is best seen in FIGURE 5. The purpose of the second crank arm 39 is to serve `as a limit means to stop the travel of the operating handle -1f8 once it reaches the rfully latched position `of FIGURE 3. This is accomplished by the crank 'arm 39 striking the backplate 21 of fthe latch base as is seen in FIGURE 6. Moreover, tension springs 40 are each fastened at one end to the crank arm 39 and at its opposite end to the itop edge of the back plate 21 as best seen in FIGURES 4 and 5. These tension springs 40 provide a counter-balancing or returning force to assist in lifting the operating handle back to its unlatched position of FIGURE 2 once the operating handle is slightly raised from its latched position of FIGURE 3. A second set of tension springs 41 are arranged -at each end of the latch mechanism to act in parallel with springs `40. This second set yof springs 41 are connected between the tips of the crank arm 34 and fingers 42 at each side of the lower portion of the operating handle 18. When the door is tightly latched the latch members 33 are nearly perpendicular with the inner surface of the door and the crank arms 34 are rotated below the pivotal axis of the rock shaft 35 as shown in FIGURE `6 to be in an over-center condition to resist the door-opening force exerted by the gasket 48 when it is compressed. This will be better understood hereinafter once a complete understanding is gained of the operation of the mechanism as a whole. A second important function of the tension springs -40 is to serve to hold the operating handle in the latched position. This function is accomplished by the tension springs 40 being carried beyond the pivotal axis of the rock shaft 35 as seen in FIGURE 6 when the operating handle 18 reaches its lowermost full latched position to give an overcenter action so that the force of the tension springs serves to increase the latching force rather than decrease it.

It is necessary to convert the vertical force bearing down on Ithe operating handle 18 to a force that will swing the latch members 33 into latching engagement with the slotted opening 38 of the oven front. This is accomplished by a pair of link members 43 each pivoted at one end to the crank arm 34 and at its opposite end to a tab 44 formed on the top edge of the side of 'the operating handle 18. A linger 45 extends from each link member 43 over the adjacent latch member 33. This linger 45 cooperates with a torsion spring of wire form 46 which is located within latch member 33 and is centered around the pivotal axis thereof on the crank arm 34 to normally swing the latch member 33 into latching engagement with the slotted opening 38 of the oven front. It would not be well to have the latch members 33 project from the inner face of the door when the door is open although this is a normal tendency of the rtorsion springs 46. However, this is avoided by the use of a xed stop 47 that extends sidewardly from the side wall 23 of the latch base so that when the crank arm 34 swings counter-clockwise from the position of FIGURE 2 to the unlatched position of the mechanism the latch members 33 will engage against the fixed stop 47 `and thereby swing counterclockwise to the more or less vertical position shown in FIGURE 4.

Hence as the operating handle 18 is depressed the crank arm 34 will swing clockwise Iand the latch member 33 will likewise move clockwise although continuing to bear against the fixed stop 47. Only when the latch member -isengaged within the slotted opening VLYS-of the oven front :do the latch members 33 move .awayfrom thefixeds'tops 47. I-hen the crank arms 341tend to Ipull 'back on the latch members while continuing 'to vlswing downwardly. This action pulls the door ytigh-tlycloseci. Theoven front is .provided .with a l)resilient -gasket -2t8 -of vsilicone yrubber lor the like which is -en-gaged by 'the inner surface-of the door 1-4 and this gasket is compressed lby lthis `tight llatching .action `of the door so that athe `door lis ltightly sealed to prevent or regulate the escape `of smoke odors, vapor, and heat from `around the door.

As seen 5in thelatched position 'of FIGURES, lthe latch members 33 aredisposed .more or.less-horizontally. When the handle 18 is raised lby exerting an upward force therefon the `tension springs 4.0 .are brought :outwardly .to pass through the Apivotal axis of therrockshatt 35 and then .the .tension of 'these ,springs 40 .and the .secondary springs 41 will quickly lreturn the operating .handle 18 to the unlatched position shown in dotted lines in FIGURE 2. Then the latch members 33 are substantially vertically disposed as best seen in FIGURE 4.

Having described above our invention of a novel latch design of rugged construction having a pair of spaced latch members 'and an operating handle capable of linear motion while the latch members have both a swinging and a tightening motion, -it will readily be apparent to those skilled in this art that the handle does not detract from the appearance `of the door and that it may be grasped both for opening and closing the door. `It is provided with operating instructions for the oven which 'are readily available when they -are necessary and are removed out of sight when they are not needed. Moreover, the door is capable of being tightly closed so as to compress the doo-r gasket and provide a good sealing action around the door opening. The latch mechanism is totally enclosed within the door when the door is opened so as not to be seen nor be in the way. While we have elected to illustrate the invention as being pant of the door it should be obvious that the parts could be reversed `and the mechanism be mounted on the door frame or range body. Then the operating handle could be manipulated by a horizontally movable lever that has an arm that is guided by the body and is connected to the handle so that horizontal movement of the lever will effect vertical movement of the operating handle in a reciprocating manner.

Other modilications of this invention will occur to those skilled in this art and it is to be understood, therefore, that this invention is not limited to the particular embodiments disclosed but that it is intended to cover all modifications which are within the true spirit :and scope of this invention `as claimed.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A latch mechanism for a pivoted door, there being a door frame element and a door element hinged along one edge to the door frame for gaining access to an opening through the door frame, the latch mechanism being supported on one of the door .and door frame elements, keeper means on fthe opposite element from the latch mechanism, the latch mechanism including an operating handle and at least one pivoted latch member, said latch member being capable of engagement with and di-sengagement from its respective keeper, said latch member being pivoted on an eccentric crank arm, a xed stop coopera-ting with said latch member as a fulcrum until the latch member engages its keeper, then the continued movement of the eccentric crank .arm pulls the latch member back so as to pull the door tightly closed, the Xed stop serving to retract the latch member into the supporting elements of the latch member when the latch mechanism is in the unlatched position.

2. A latch mechanism for locking Ia pivoted door in a closed position, there being a ldoor trame element and a door element hinged along one edge to the door frame for gaining access therethrough, the latch mechanism being supported on one ofthe door and door frame elements, a

Y 6 pair -of keepers V01:1 lthe opposite `element from l:the latch mechanism, .the latch mechanism including an operating handle that iscapable of reciprocating amovement and -a `pair of `pivoted latch members which swing `in parallel planes, usaid r`latch members *being joined vr'together lby `a 'rock shaft :and being 'mounted en 'cnank rarms 'of Ithe rock shaft so as to 'becapa'bleof `engagement vwith'a-ntl disengagement strom the respective keepers, and linkmeansconmeeting -the oper-atin-g 4handle to Athe lcrank farms "of the krock shaft so that linear motion of the operating handle will aifect swinging motiono'f `the latchmernbers vso the 'latch members will engage within the keepers 'on `the cpposite element, the Alast portionlof Athe swinging movement on 'the latch member tending ito pull the `-door` 'closed tightly, and return spring means -connected between the rock shaft and Lthe elementen-which `the latch 'mechanism is supported which cooperates with the rock shaft for locking't'he latch ymechanism inthe latched position by 'ian over-center travel -of the .spring, tthe return spring also serving as a counter-balance spring to lassist 'in moving the :operating handle to the unlatched position after the operating handle is shifted slightly from the latched position.

3. A latch mechanism las recited in claim 2. with the laddition of fixed stop means cooperating with each latch member as a fulcr-um until the latch members swing out `and engage the respective keepers, then the continued movement of the crank arms of the rock shaft pull the latch members back so las to pull the door tightly closed, the xed stop means serving to retract the latch members into the supporting element of the latch mechanism when the latch mechanism is in the unlatched position.

4. A latch mechanism for |an oven door, there being a door vframe Iand la front opening drop door hinged along the 'bottom edge of the door frame, the latch mechanism being `supported within the door along the top edge thereof, `a pair of keepers formed in the front -face of the door frame ne-ar the top thereof, said latch mechanism including a supporting base xedly mounted within the door structure, said supporting hase including side bearing rails, and an operating handle supported for sliding engagement on the said side bearing rails, the operating handle extending outwardly through the front of the door and being capable of linear motion, the latch mechanism including a parallel pair of pivoted latches that are joined together on a rock shaft which is in turn pivotally supported from the latch hase, the latches serving to lact in unison land `be-ing capable of engagement with and disen- `gagement from the respective keepers, the latclhes being freely supported on crank arms of the rock shaft, there being .spring means exterted against the latches to normally urge the latches into la latched position, and link means joining the operating handle with the cnank arms of the rock shaft so that linear motion of the operating handle will laffect swinging movement of the latches, the crank iarms serving to pull the latches back so as to pull the door tightly closed once the latches engage the keepers.

5. A latch mechanism las recited in claim 4 with the addition of xed stop means )cooperating with each latch to serve as a iulcrurn therefor until lthe latches engage their respective keepers, then the continued movement of the crank arms will pull the latches hack so :as to pull the door closed tightly, the fixed stop means serving to retract the latch member into the door when the latch mechanism is in the unlatched position.

6l. A latch mechanism as recited in claim 5 with the addition of spring means connected with the rock shaft so that when the crank :arm swings to the latched position the spring will be moved over-center to provide la biasing force tending to hold the operating handle in the latched position, this spring means also serving fas a counterb-al-ance for returning the handle to its unlatched position once the handle has been moved slightly from its latched position.

7. A latch mechanism for a pivoted door comprising a latch base iixedly mounted within the door and a latch operating handle slidably supported for linear motion on the latch base, the handle having a hand-engageable portion extending through ran opening in the iront face of the door, latch means pivotally mounted about a swinging pivot means that is supported from the latch Ibase, and link means pivotally connected -between the latch means and the handle so that linear motion of the handle will Veffect swinging motion 0f the latch means; the latch means lbeing retractable completely Within the door when the door is open, said latch means being pulled hack With- `in the door as 'it approaches a fully latched position so `as to close and hold the door tightly, said latch means being substantially perpendicular to the inner surface of ,the ldoom when the latch means is engaged a keeper in the fully latched position.

8. A latch mechanism as recited in claim 7 wherein the latch base includes lixed stop means that is engaged Iby the latch means when the door is -unlatched so as to retnact the latch means completely within the door when the door is open.

9. A latch mechanism las recited in claim 8, wherein spring means 'bia-s the handleinto the nnlatched position as well as hold the handle in the fully latched position against inadvertent opening of the latch.

l0. A latch mechanism las recited in lclaim 7 wherein the latch means includes at least two latch members that are pivotally supported on crank )arms at the ends of a rock shaft, .and a door fname on which the door is hinged, said door fname having a pair of slotted open-ings Kserving as vkeepers for receiving the latch members.

References Cited in the file of this patent UNITED STATES PATENTS 927,240 Holman July 6, 1909 2,274,711 Knause Mar. 3, 1942 2,378,654 Pekny June 19, 1945 2,789,852 Eads n Apr. 23, 1957 

1. A LATCH MECHANISM FOR A PIVOTED DOOR, THERE BEING A DOOR FRAME ELEMENT AND A DOOR ELEMENT HINGED ALONG ONE EDGE TO THE DOOR FRAME FOR GAINING ACCESS TO AN OPENING THROUGH THE DOOR FRAME, THE LATCH MECHANISM BEING SUPPORTED ON ONE OF THE DOOR AND DOOR FRAME ELEMENTS, KEEPER MEANS ON THE OPPOSITE ELEMENT FROM THE LATCH MECHANISM, THE LATCH MECHANISM INCLUDING AN OPERATING HANDLE AND AT LEAST ONE PIVOTED LATCH MEMBER, SAID LATCH MEMBER BEING CAPABLE OF ENGAGEMENT WITH AND DISENGAGEMENT FROM ITS RESPECTIVE KEEPER, SAID LATCH MEMBER BEING PIVOTED ON AN ECCENTRIC CRANK ARM, A FIXED STOP COOPERATING WITH SAID LATCH MEMBER AS A FULCRUM UNTIL THE LATCH MEMBER ENGAGES ITS KEEPER, THEN THE CONTINUED MOVEMENT OF THE ECCENTRIC CRANK ARM PULLS THE LATCH MEMBER BACK SO AS TO PULL THE DOOR TIGHTLY CLOSED, THE FIXED STOP SERVING TO RETRACT THE LATCH MEMBER INTO THE SUPPORTING ELEMENTS OF THE LATCH MEMBER WHEN THE LATCH MECHANISM IS IN THE UNLATCHED POSITION. 